Dinitropyrazole derivatives, their preparation, and energetic compositions comprising them

ABSTRACT

The present invention provides:
         dinitropyrazole derivatives of formula (I)       

                         
in which: R═NO 2 , NH 2 , NF 2 , NHOH, OH or NHNH 2  and R′═H when R═NH 2 , NF 2 , NHOH, OH or NHNH 2  or R′═H, NH 2  or a linear or branched C 1 -C 4  alkyl group, optionally substituted by at least one hydroxy and/or one fluoro group, when R═NO 2 ; other than 4-amino-3,5-dinitropyrazole; and also the salts of said derivatives of formula (I) in which R′═H;
         the preparation of said derivatives and of their salts; and   energetic compositions comprising at least one of said derivatives and/or at least one salt of such a derivative.

This application is a C.I.P. of International patent applicationPCT/IB2008/002535 filed on Jun. 6, 2008.

FIELD OF THE INVENTION

The present invention relates to:

-   -   new heterocyclic molecules: new derivatives of dinitropyrazoles        (of 3,5-dinitropyrazole and of 3(5),4-dinitropyrazole);    -   the preparation of said new molecules;    -   energetic compositions comprising such molecules; and    -   synthesis intermediates, which are new products, useful in the        preparation of said new molecules.

These new compounds (these new molecules) are of particular advantage inthat they exhibit both a high energetic performance and a reducedvulnerability.

BACKGROUND ART

Reduced vulnerability munitions (known as MURAT for MUnition with RiskATtenuation), developed a decade and a half ago, necessitate the use ofexplosive molecules of little or no sensitivity. These molecules arerequired to possess a sensitivity which is as low as possible, whileretaining a heightened level of energetic performance. But these twoproperties are difficult to reconcile. For instance, cyclotetramethylenetetranitramine (octogen) is the most widespread explosive to date, buthas a level of insensitivity (essentially to impact) which is inadequatefor application to MURAT-type munitions. 3-Nitro-1,2,4-triazol-5-one(ONTA), for its part, is an energetic molecule which is entirelyexceptional in terms of insensitivity, being markedly less sensitivethan octogen, for example. On the other hand, its level of energeticperformance is lower than that of octogen. The same is true of otherlow-sensitivity explosive molecules, such as1,3,5-triamino-3,4,6-trinitrobenzene (TATB),1,1′-diamino-2,2′-dinitroethylene (FOX-7) or4,6-di-(3-amino-5-nitro-1,2,4-triazole)-5-nitropyrimidine (FR2,624,118).

The skilled worker is constantly looking for new energetic moleculeswhich offer an advantageous tradeoff in terms of performance andvulnerability while retaining a level of thermal stability that meetsthe demands of the application. Such molecules advantageously exhibitcharacteristics of thermodynamic decomposition that allow them to beused in the fields of propulsion and of explosives.

Lebedev et al. showed calculated and/or measured results ofphysico-chemical properties and of performances for energetic compounds(INTERNATIONAL ANNUAL CONFERENCE OF ICT, vol. 29, 1 janvier 1998, p.180.1-180.13). The developed chemical formulae of said compoundstogether with said results are shown in Tables. It has to be emphasizedthat the synthesis (that any process for the preparation) of theconcerned compounds, more particularly the one of compounds of formulaVII, VIII, IX, are neither disclosed, nor suggested. To the inventor'sknowledge, no additional information has since been published related tothese compounds and their process of preparation, except information on4-amino-3,5-dinitro-1-pyrazole (compound of formula IX) (see thefollowing paragraph). The inventor notably discloses a non obviousprocess for the preparation of the 5-amino-3,4-dinitro-1-pyrazolefurther in the present text (within the scope of the present invention).

R. D. Schmidt, G. S. Lee, P. F. Pagoria, A. R. Mitchell and R. Gilardi,in J. Heterocyclic Chem. 2001, 38, 1227, described the synthesis andproperties of a new explosive: 4-amino-3,5-dinitro-1-pyrazole (LLM-116).This new explosive is presented as being advantageous in reference tothe tradeoff referred to above: sensitivity/performance. Nevertheless,it has the major disadvantage of dissolving small polar organicmolecules such as DMSO and of undergoing hydration in the presence ofwater. However, the product is advantageous, in performance terms, onlyif it is free from any trace of impurity, and the purification anddehydration process is long and laborious.

The skilled worker is therefore still looking for new energeticmolecules which comply with the specification set out above and which,furthermore, advantageously, can be synthesized readily.

SUMMARY OF THE INVENTION

The present invention provides, in accordance with its first subject, anew class of energetic molecules. These energetic molecules are newdinitropyrazole derivatives, new derivatives of 3,5-dinitropyrazole andof 3(5),4-dinitropyrazole. Said derivatives conform to the formula (I)below:

in which: R═NO₂, NH₂, NF₂, NHOH, OH or NHNH₂;

-   -   R′═H when R═NH₂, NF₂, NHOH, OH or NHNH₂, or    -   R′═H, NH₂ or a linear or branched C₁-C₄ alkyl group, optionally        substituted by at least one hydroxy and/or one fluoro group,    -   when R═NO₂.

It is appropriate to exclude 4-amino-3,5-dinitropyrazole from said newclass, since it has already been described (see above).

The compounds of the invention—new derivatives ofdinitropyrazoles—accordingly consist of:

-   -   the compounds of formula (I) above in which R′═H; in other        words, the compounds conforming to the following formula:

in which: R═NO₂, NH₂, NF₂, NHOH, OH or NHNH₂ (with the exception of4-amino-3,5-dinitropyrazole); and

-   -   the N-substituted 3,4,5-trinitropyrazoles identified above,        conforming to the formula (Ic) below.

The new derivatives of the invention, in the neutral acid form (R′═H),are capable of existing in the form of salts, of formula (I′):

in which C⁺ represents a cation.

Said salts form an integral part of the first subject of the presentinvention.

The skilled worker has already understood that the compounds of theinvention of formula (I) in which R′═H (in neutral acid form or in saltform) exist as two families, that of the derivatives of3,5-dinitropyrazole (of formulae Ia and I′a below) and that of thederivatives of 3(5),4-dinitropyrazole (of formulae Ib and I′b below);with 3,4,5-trinitropyrazole and its salts being common to both saidfamilies:

in which: R═NO₂, NF₂, NHOH, OH or NHNH₂;

in which: R═NO₂, NH₂, NF₂, NHOH, OH or NHNH₂.

The invention further provides compounds of formula (I) in which R′ isother than H, more specifically 3,4,5-trinitropyrazole derivatives whichconform to the formula (Ic) below:

in which R′═NH₂ or a linear or branched C₁-C₄ alkyl group which isoptionally substituted by at least one hydroxy group and/or onefluorine.

R′ is an amino group or a lower alkyl group (containing 1 to 4 carbonatoms), which is optionally substituted. Said lower alkyl group may belinear or branched. It is selected from methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl and tert-butyl groups and is unsubstitutedor substituted by at least one hydroxy group and/or at least onefluorine. More particularly it may consist of a perfluorinated loweralkyl group. According to one advantageous variant, R′ is an amino group(—NH₂) or a methyl group (—CH₃). Very advantageously it is a methylgroup.

These compounds of the invention, of formula (I) in which R═NO₂ and R′is other than H, have a melting point which is lower than that of thecompounds of the invention of formula (I) in which R′═H. Their energeticpower, which is reduced to a greater or lesser extent, remains ofinterest owing to the presence of the three nitro groups. Said compoundsmay in any case be doped by their joint use with at least one other,more highly performing energetic molecule, of the type for example ofRDX (cyclotrimethylene trinitramine or hexogen), HMX(cyclotetramethylene tetranitramine or octogen), CL20(2,4,6,8,10,12-hexanitrohexaazaisowurtzitane or HNIW), or anothernitrogen-containing heterocycle known to date (see later on below).

The low melting point of said compounds is of particular interest. Itallows each of the said compounds to be formulated as a melt-castexplosive by a method (of explosives manufacture) that is familiar tothe skilled worker. Said method does not involve a binder and does notinclude powder tableting. It consists primarily in melting the energeticcompound or compounds in question by a simple raising of thetemperature, and then in causing the melted mass to crystallize bysimple cooling. Advantageously the melted mass is filled with at leastone other, more highly performing, energetic molecule (moreparticularly, of the types identified above).

N-Methyl-3,4,5-trinitropyrazole is thus a particularly interestingcompound of the invention in that it combines a low melting point (91.3°C.) with interesting energetic properties (more particularly it exhibitsan oxygen balance significantly greater than that of TNT).

In the context of its first subject, therefore, the present inventionencompasses the new compounds of formula (I) identified below:

-   -   4-hydroxy-3,5-dinitropyrazole,    -   4-hydroxylamino-3,5-dinitropyrazole,    -   4-hydrazino-3,5-dinitropyrazole,    -   4-difluoramino-3,5-dinitropyrazole,    -   5-hydroxy-3,4-dinitropyrazole,    -   5-amino-3,4-dinitropyrazole,    -   5-hydroxylamino-3,4-dinitropyrazole,    -   5-hydrazino-3,4-dinitropyrazole,    -   5-difluoramino-3,4-dinitropyrazole,    -   3,4,5-trinitropyrazole,    -   the salts of said compounds,    -   N-methyl-3,4,5-trinitropyrazole, and    -   N-amino-3,4,5-trinitropyrazole.

Particular preference is given to the compounds of formula (I) below:

-   -   3,4,5-trinitropyrazole,    -   4-hydroxy-3,5-dinitropyrazole,    -   4-hydroxylamino-3,5-dinitropyrazole,    -   5-hydroxy-3,4-dinitropyrazole,    -   5-amino-3,4-dinitropyrazole,    -   5-hydroxylamino-3,4-dinitropyrazole,    -   their salts,    -   N-methyl-3,4,5-trinitropyrazole, and    -   N-amino-3,4,5-trinitropyrazole.

With regard to the salts of the compounds of the invention (those offormula (I) in which R′═H), it may be said, without any limitation, thatthey conform advantageously to the formulae (I′), (I′a) or (I′b) abovein which C⁺ represents:

-   -   an alkali metal cation (such as Li⁺, Ca⁺, K⁺, Cs⁺),    -   an alkaline earth metal cation (such as Mg²⁺, Ba²⁺),    -   an ammonium cation,    -   a substituted ammonium cation (substituted more particularly by        a hydroxyl group (hydroxylammonium), by lower alkyl groups        (C₁-C₆, advantageously C₁-C₄, alkyl) and/or aryl groups, which        are themselves optionally substituted; the presence of such        substituents allows the energetic power of the compounds to be        modified),    -   a hydrazinium cation,    -   a guanidinium cation,    -   an aminoguanidinium cation,    -   a diaminoguanidinium cation,    -   an iminium cation.

The compounds of the invention are energetic compounds of lowsensitivity, or even no sensitivity, which are highly performing. Theirlevel of energetic performance is equivalent, or in some cases evensuperior, to that of octogen, for levels of sensitivity which arecomparable with those of ONTA. Said compounds of the invention aretherefore particularly advantageous:

in that they are both highly energetic and of reduced vulnerability;

in that they comply, in a particularly advantageous way, with thespecification below:

-   -   energetic performance levels higher than those of ONTA or than        those of TATB;    -   very low sensitivity;    -   high thermal stability (required for the intended applications).

The statements above are demonstrated in the example section further onin the present text.

According to a second subject, the present invention provides thepreparation of the new compounds of the formula (I) and their salts.

The majority of compounds of formula (I) can be obtained from “newprecursors” which belong to the family of the trinitropyrazoles (1,3,4and 3,4,5 isomers), which are themselves obtained from knowndinitropyrazoles. The compounds of formula (I) (in which R′═H) inquestion are obtained by substitution on trinitropyrazole heterocycles.

The known dinitropyrazoles conform to the formulae specified below andaccordingly have been described in the literature. The formulae andcorresponding bibliographic references are indicated below.

described in J. Heterocyclic Chem. 2001, 38, 1227 (see above);

described in J. Org. Chem. 1973, 38, 1777 (by J. W. A. M. Janssen, H. J.Koeners, C. G. Kruse, C. L. Habraken).

The trinitropyrazoles—“new precursors”—conform to the formulae below:

The first of them—3,4,5-trinitropyrazole—is a compound of the invention(of formula (I) in which R═NO₂ and R′═H), which can be used as aprecursor for the preparation of other compounds of the invention:

those of formula (Ia) in which R═NH—NH₂, OH and NHOH (see below); and

those of formula (Ic) in which (R═NO₂ and) R′ is other than H.

The second of them—1,3,4-trinitropyrazole—is a new intermediate which isuseful in the preparation of compounds of the invention (of formula (Ib)in which R═NH—NH₂, OH, NHOH, NH₂ and NF₂).

Described below in greater detail is the second subject of the presentinvention, namely the process for preparing the compounds of formula (I)and their salts.

Said process comprises:

A) for preparing 4-difluoroamino-3,5-dinitropyrazole:

-   -   fluorinating 4-amino-3,5-dinitropyrazole;        B) for preparing other compounds of formula (I) in which R′═H:    -   obtaining an isomer of trinitropyrazole selected from        3,4,5-trinitropyrazole and the 1,3,4-trinitropyrazole        intermediate, respectively, by oxidizing        4-amino-3,5-dinitropyrazole or nitrating 3,5-dinitropyrazole and        by nitrating 3,4-dinitropyrazole;    -   carrying out a substitution:    -   + on said 1,3,4-trinitropyrazole intermediate, to give        3,4-dinitropyrazoles substituted in position 5 by the radical        R═NH—NH₂, OH, NHOH or NH₂;    -   + on said 3,4,5-trinitropyrazole, to give 3,5-dinitropyrazoles        substituted in position 4 by the radical R═NH—NH₂, OH or NHOH;    -   fluorinating the resulting 5-amino-3,4-nitropyrazole to give        5-difluoroamino-3,4-nitropyrazole;        C) for obtaining a salt, reacting the resulting compound of        formula (I) (in which R′═H) with a base; and        D) for preparing a compound of formula (I) in which R′≠H:    -   obtaining 3,4,5-trinitropyrazole by oxidation of        4-amino-3,5-dinitropyrazole, nitration of 3,5-dinitropyrazole,        oxidation of 5-amino-3,4-dinitropyrazole or diazotization of        said 5-amino-3,4-dinitropyrazole, said        5-amino-3,4-dinitropyrazole having been prepared as indicated        above;    -   obtaining its anion;    -   carrying out a nucleophilic substitution on said anion.

The different steps of sections A and B above are given in the reactionscheme below.

Specified below are each of said steps, leading to the preparation ofthe trinitropyrazole intermediate (1,3,4-trinitropyrazole) and of eachof the compounds of formula (I).

-   -   4-Difluoroamino-3,5-dinitropyrazole is obtained directly by        fluorination of 4-amino-3,5-dinitropyrazole (known starting        product). In the same way, the fluorination of        5-amino-3,4-dinitropyrazole (product of the invention prepared        beforehand) leads to 5-difluoroamino-3,4-dinitropyrazole. The        conventional and long-established methods of fluorination, more        particularly those described in J. Org. Chem. 1968, 33, 1008-11,        are ideally suitable.    -   3,4,5-Trinitropyrazole can also be obtained, directly, by three        different synthesis routes:    -   + by oxidation of 4-amino-3,5-dinitropyrazole (or of its isomer        5-amino-3,4-dinitropyrazole).

Indeed, it is noted that said trinitropyrazole may in the same way beobtained by oxidation of 5-amino-3,4-dinitropyrazole preparedbeforehand. The oxidation reaction, in one context or the other, isadvantageously carried out in concentrated peroxides. A concentratedmixture of H₂O₂+H₂SO₄ is suitable for the oxidation of deactivatedamines. Selective extraction of the medium is necessary. It isadvantageous to use dichloromethane as the extraction solvent. Examples3 and 4 below illustrate an oxidation of this kind;

-   -   + by diazotization of 5-amino-3,4-dinitropyrazole (prepared        beforehand).

Operation takes place in solution in a concentrated inorganic acid, suchas, for example, 20% sulfuric acid. More highly concentrated acids maybe employed, without recording any notable effect on the yield. Theintermediate diazonium salt is converted to trinitropyrazole by heatingthe acidic solution in the presence of sodium nitrite. Example 3′ belowillustrates a diazotation of this kind. The same diazotization reactionstarting from 4-amino-3,4-dinitropyrazole appears to be more awkward tocarry out, owing to the superior stability of the diazonium salt (onthis point reference may be made to I. L. Dalinger, T. I. Cherkasova, S.A. Shevelev, Mendeleev Commun. 1997, 58);

-   -   + by nitration of 3,5-dinitropyrazole, under severe conditions.

The Applicant has indeed shown that the nitration of3(5),4-dinitropyrazole, under moderate temperature conditions (between0° C. and ambient temperature), leads to the selective formation of1,3,4-trinitropyrazole (see below), while the nitration of3,5-dinitropyrazole, under severe conditions (more particularly asregards temperature), leads to the selective formation of3,4,5-trinitropyrazole. The preparation of 1,3,4-trinitropyrazole (newintermediate) is specified below. With regard to the nitration of3,5-dinitropyrazole, which leads directly to 3,4,5-trinitropyrazole, itis carried out in a sulfonitric (H₂SO₄+HNO₃) or phosphonitric(H₃PO₄+HNO₃) medium, containing from 0 to 100% by mass of sulfuric,phosphoric or nitric anhydride (referred to as oleums), at a temperaturebetween 50° C. and the boiling temperature of the medium. This route tothe 3,4,5-trinitropyrazole of the invention—an original and particularlyadvantageous route to a high-performance compound—is illustrated inExample 5 below.

-   -   1,3,4-Trinitropyrazole—new intermediate—is therefore obtained by        nitration, under moderate temperature conditions (see above), of        3(5),4-dinitropyrazole. Such a nitration may be carried out at        ambient temperature in an acetonitric (HNO₃+acetic anhydride)        mixture or equivalent mixture, such as mixtures of        HNO₃+trifluoroacetic anhydride. A nitration of this kind in an        acetonitric mixture is illustrated in Example A below. It has        been shown, moreover, in the context of the invention, that        nitronium solutions are likewise suitable. The solutions of        nitronium ions may be generated directly from nitronium salts        (such as NO₂BF₄), or from nitric acid catalyzed by H₂SO₄. A        procedure of this kind is illustrated in Example B below.    -   Starting from said 3,4,5-trinitropyrazole (compound of the        invention, of formula (I) in which R═NO₂), it is possible, by        nucleophilic substitution, to obtain other compounds of        formula (I) (in which R═H) of the invention. Starting from said        1,3,4-trinitropyrazole (new intermediate) it is possible, by        substitution, to obtain other compounds of formula (I) (in which        R═H) of the invention The substitution reactions are carried out        in the presence of inorganic bases such as solutions of        hydroxides, ammonia, hydrazine, and hydroxylamine to form the        appropriately substituted dinitropyrazoles of formula (I). The        hydroxide solutions may be generated starting from hydrogen        carbonate, carbonate, hydroxide (sodium or potassium hydroxide),        or nitrite salts or even water. The reactions may be carried out        in water or in organic solvents such as dimethylformamide,        dimethyl sulfoxide, tetrahydrofuran, acetonitrile, nitromethane,        sulfolane, and mixtures thereof. Said reactions may be carried        out at a temperature between temperatures lower than 0° C. and        the reflux temperature of the solvent used. Preferably the        substitution reactions of 3,4,5-trinitropyrazole are performed        at high temperatures (reflux) and the substitution reactions of        1,3,4-trinitropyrazole are performed at low temperature. In        fact, as described in the article by Habraken and Poels (J. Org.        Chem. 1977, 42, 2893), the substitution reactions on        1,4-dinitropyrazole derivatives, such as 1,3,4-trinitropyrazole,        lead to the functionalization of the 5 position of the pyrazole        and to substitution of the N-nitro. In contrast, under more        vigorous conditions, the nucleophilic substitution on the        3,4,5-trinitropyrazole takes place, unexpectedly, on the        carbon (4) of the pyrazole.

To obtain 5-amino-3,4-dinitropyrazole, the substitution reactionconcerned is an amination. The techniques of amination that are knownare numerous. Mention may be made, for example, of the reaction withammonia (mentioned above), the method of Gabriel (via the phthalamidederivative), and the reduction of an azide derivative. Advantageously itis possible thus to prepare, selectively, 5-amino-3,4-dinitropyrazole,in two steps:

-   -   the reaction of azide salts with 1,3,4-trinitropyrazole to form        5-azido-3,4-dinitropyrazole, a new compound (see, for        illustration, Example C below);    -   the reduction of said 5-azido-3,4-dinitropyrazole by        conventional methods, such as the action of a trisubstituted        phosphine or of thiolacetic acid (see, for illustration,        Examples 1 and 2 below).

These two steps are shown schematically below:

It is recalled, incidentally, that said 5-amino-3,4-dinitropyrazole isable, by oxidation or diazotization, to give 3,4,5-trinitropyrazole (seeabove);

and is able, by fluorination, to give4-difluoroamino-3,5-dinitropyrazole (see above).

To obtain a salt of any one of the compounds of formula (I) in whichR′═H, said compound is reacted with the appropriate base (of formulaCOH, according to the formula of the salts that was given above).

For preparing an N-substituted 3,4,5-trinitropyrazole, therefore, the3,4,5-trinitropyrazole as obtained at the outcome of any one of the fourpathways shown in the reaction scheme above and described above(oxidation of 4-amino-3,5-dinitropyrazole or of5-amino-3,4-dinitropyrazole, nitration of 3,5-dinitropyrazole ordiazotization of 5-amino-3,5-dinitropyrazole) is used.

The reaction scheme is as follows:

In the presence of an organic or inorganic base, such as NaOH, KOH, NaH,an alkoxide or pyridine, the anion of 3,4,5-trinitropyrazole isobtained. This anion, in the presence of an appropriate electrophile,undergoes a nucleophilic substitution which gives rise to the expectedcompound.

The methyl compound, for instance, may be obtained by the action of aconventional methylating agent, such as methyl iodide, methyl triflate,diazomethane or trimethyloxonium salts. The other alkyl compounds may beobtained analogously.

For instance, the amino compound may be obtained by electrophilicamination, by the action of a conventional electrophilic aminatingagent, such as chloramine (NH₂Cl), hydroxylamine-O-sulfonic acid (HOSA,NH₂—O—SO₃H), dinitrophenoxy-O-hydroxylamine,trinitrophenoxy-O-hydroxylamine (or Pic-O—NH₂=hydroxylamine of picricacid).

The conditions for implementation of the nucleophilic substitution areconventional per se. The original feature is the precise nature of theanion in question.

According to the third of its subjects, the present invention providesthe new intermediates which are useful in preparing the compounds offormula (I) (and their salts). Said new intermediates, identified in theabove description of the process, consist of:

-   -   1,3,4-trinitropyrazole; and    -   5-azido-3,4-dinitropyrazole.

The new compounds of formula (I) of the invention:

-   -   as identified above, in general form (formulae (I), (Ia), (Ib)        and (Ic)) and specifically (see the list of said compounds set        out earlier), and/or    -   as (readily) obtainable by the process described above (limited        to a single step (for obtaining 3,4,5-trinitropyrazole and        obtaining 4-difluoroamino-3,5-dinitropyrazole) or comprising,        more generally, 2 or 3 steps (for obtaining other compounds of        formula (I) in which R′═H) exhibit energetic characteristics        which are particularly advantageous (with regard to the        sensitivity/performance tradeoff and to the thermal stability).        Their performance characteristics are advantageous for both        propellant applications and explosive applications.

The compounds of the invention (and their salts) clearly constituteadvantageous competitors to the insensitive energetic moleculesrepresented by ONTA, TATB and I-RDX®. They are serious candidates forMURAT-type applications in explosives and in propellants of greatlyreduced vulnerability relative to conventional propellants.

According to its third subject, therefore, the present inventionprovides energetic compositions comprising at least one compound offormula (I) (in which R′═H or R′≠H) and/or at least one salt of such acompound (of formula (I) in which R′═H), as described above.

The determination of the effective amount of said at least one compoundand/or salt is within the scope of the skilled worker, in view of theexact end use desired for said energetic compositions. Said energeticcompositions may more particularly consist of explosive compositions orpropellant compositions. These two types of energetic compositions (withconventional energetic molecules) are familiar to the skilled worker.

The energetic compositions of the invention of the first type—explosivecompositions—contain or do not contain binder (inert or energetic). Theygenerally contain at least 20% by mass of at least one compound offormula (I) (in which R′═H or R′≠H) and/or of at least one salt of sucha compound (of formula (I) in which R′═H), very generally at least 50%by mass of such a compound of formula (I) (idem) and/or at least onesalt of such a compound (idem). They are entirely able to containbetween 90% by mass and 100% by mass of at least one such compound offormula (I) (idem) and/or of at least one salt of such a compound(idem).

The energetic compositions of the invention of the secondtype—propellant compositions—contain a binder, inert or energetic. Theygenerally contain not more than 80% by mass of at least one compound offormula (I) (in which R′═H or R′≠H) and/or of at least one salt of sucha compound (of formula (I) in which R′═H), very generally not more than50% by mass of a compound of formula (I) (idem) and/or of at least onesalt of such a compound (idem).

The energetic compositions of the invention for which a specificationhas been given above, in no way limitatively, of the amount ofcompound(s) of the invention (compound(s) of formula (I) in which R′═Hor R′≠H and/or salts of compounds of formula (I) in which R′═H) arecompositions which are generally obtained by tableting a powder or withinvolvement of a binder (at a more or less considerable level).

Obviously also an integral part of the third subject of the presentinvention (i.e., energetic compositions comprising at least one compoundor salt of the invention) are the energetic compositions of melt-casttype which comprise at least one compound of the invention which has alow melting point, in other words at least one compound of formula (I)in which R′≠H (and R═NO₂).

Said melt-cast energetic compositions comprise at least one suchcompound (generally one such compound) or at least one such compound(generally one such compound) with at least one other, known energeticmolecule which is more highly performing. Said at least one otherenergetic molecule is advantageously selected from conventionalenergetic molecules such as HMX, RDX, CL20 and anothernitrogen-containing heterocycle (see above).

The presence of at least one other (more highly performing) energeticmolecule of this kind is not mandatory; it is advantageous. Generally,when it is present, at least one other energetic molecule of this kindis present at from 10% to 80% by mass. Its presence at a level of 60% bymass is especially recommended.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a structure of a first product of the invention using x-raydiffraction.

FIG. 2 shows a structure of a second product of the invention usingx-ray diffraction.

FIG. 3 shows a structure of a third product of the invention using x-raydiffraction.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will now be illustrated by the examples below.

Examples A, B and C illustrate the preparation of synthesisintermediates.

Examples 1 to 6 illustrate the preparation of dinitropyrazolederivatives according to the invention: of formula (I) in which R═NH₂,NO₂, OH (see Table 1 below) and R′═H. The properties and performancecharacteristics of these compounds are of interest (see Tables 2 to 4below). Attached FIGS. 1, 2, and 3 show the structures of said compoundsas determined by means of X-rays.

Examples 7 and 8 illustrate the preparation of N-substituted3,4,5-trinitropyrazoles.

Example A

200 mg of 3,4-dinitropyrazole are introduced into 7 mL of aceticanhydride containing 1.4 mL (2.13 g) of concentrated nitric acid at 0°C. The temperature is allowed to rise to 15° C., and the mixture is thenstirred at this temperature for 18 hours. The reaction mixture is pouredonto 70 g of ice and then the product is extracted with dichloromethane.The chlorinated organic phase is dried over magnesium sulfate and thenfiltered and concentrated under vacuum. 200 mg of crude product arerecovered in this way. The 1,3,4-trinitropyrazole is purified on silicagel with elution with a hexane/AcOEt (2/0.5, v/v) mixture. 34 mg ofpure, colorless liquid are recovered (13% yield). ¹H NMR (acetone): 8.49(s, CH); ¹³C NMR (acetone): 128.6 (CH), 128.4 (CNO₂, broad), 145.1 (t,CNO₂); ¹⁴N NMR (acetone): 310.3, 314, 351.5 ppm. DSC: decompositiontemperature: 191° C.

Example B

With argon blanketing at 0° C., 200 mg of 3,4-dinitropyrazole areintroduced into 20 mL of anhydrous acetonitrile containing 193 mg ofnitronium tetrafluoroborate. The reaction mixture is then left to reactat ambient temperature for 18 hours. It is subsequently concentratedunder vacuum, then treated with 30 mL of ice-water and extracted withdichloromethane. The recovery and purification phase is identical tothat described in Example A. Purification gives 121 mg of pure,colorless liquid (47% yield).

Example C

A solution of 1,3,4-trinitropyrazole, described in Examples A and B,diluted in 5 mL of tetrahydrofuran is poured slowly into a stirredsuspension of sodium azide in dimethyl sulfoxide (28 mL) at ambienttemperature. After 1 hour of stirring, the reaction mixture is pouredonto 280 g of ice, then acidified to a pH of 1 using 37% hydrochloricacid solution. The mixture is extracted with 60 mL of diethyl ether. Theorganic phase is recovered and then washed with 0.1 N HCl, dried overmagnesium sulfate, and concentrated under vacuum. The product issubsequently triturated in 10 mL of dichloromethane until a yellow solidis obtained. The 5-azido-3,4-dinitropyrazole is filtered and then driedunder vacuum for 30 minutes. This gives 220 mg of yellow solid, which isused as it is in the subsequent phase (23% yield). ¹H NMR (acetone): nosignal. ¹³C NMR (acetone) (ppm): 118.1 (Q), 140.6 (Q), 150.1 (Q). ¹⁴NNMR (acetone) (ppm): 357.1 (NO₂), 355.4 (NO₂), 310.3 (N₃), 231. DSC:melting point: 141.3° C.; decomposition temperature: 156.7° C.

Example 1

200 mg of 5-azido-3,4-dinitropyrazole are reduced in 10 mL ofthiolacetic acid at ambient temperature for 2 days. Subsequently 20 mLof hexane are poured in to precipitate the product. 50 mg of yellowsolid are recovered in this way by filtration (28% yield).

The structural formula of said product and the results ofphysicochemical analyses (¹H, ¹³C, and ¹⁴N NMR and MS), which confirmthe structure, are given in Table 1 below.

Example 2

At ambient temperature and in one portion, 287 mg of triphenylphosphineare added to 20 mL of tetrahydrofuran containing 200 mg of5-azido-3,4-dinitropyrazole. The reaction mixture is stirred at ambienttemperature for 18 hours and then 5 mL of distilled water are added. Thereaction mixture is left to react at reflux for 20 hours. Subsequently10% sodium hydroxide solution is added in order to raise the pH to10-11. The reaction mixture is washed with ethyl acetate twice (20 mL),then acidified to an acid pH of 1 using 10% hydrochloric acid. Theproduct is subsequently extracted with 20 mL of diethyl ether (3 times).The ethereal phases are combined and then washed with saturated sodiumchloride solution, dried over sodium sulfate, and concentrated undervacuum. The product is subsequently triturated in 20 mL ofdichloromethane, before being filtered and dried. This gives 65 mg ofred solid (51% yield).

The structural formula of said product and the results ofphysicochemical analyses (¹H, ¹³C, and ¹⁴N NMR and MS), which confirmthe structure, are given in Table 1 below.

Example 3

600 mg of 5-amino-3,4-dinitropyrazole are added all at once to awell-stirred mixture of sodium persulfate (3 g), 60% hydrogen peroxide(2.5 g), and concentrated sulfuric acid (4 g) at ambient temperature.The reaction mixture is stirred for 8 hours and then extracted 5 timeswith dichloromethane (5*20 mL). The chlorinated phases are combined andare dried over magnesium sulfate, filtered, and then concentrated undervacuum. This gives 217 mg of pure product (31% yield).

The structural formula of said product and the results ofphysicochemical analyses (¹H, ¹³C, and ¹⁴N NMR and MS), which confirmthe structure, are given in Table 1 below.

Example 3′

650 mg of sodium nitrite are added rapidly at 0-10° C. to a 20% solutionof sulfuric acid (5 mL) containing 145 mg of5-amino-3,4-dinitropyrazole. The mixture is left to react at thistemperature for 1 hour and then the cold mixture is poured into 40 mL of10% strength aqueous sodium nitrite which is maintained at 20° C. Themixture is subsequently heated at 50-60° C. for 30 minutes until theeffervescence disappears completely. The excess sodium nitrite is thenneutralized by addition of concentrated sulfuric acid. The reactionmixture is extracted 3 times with ethyl acetate. The organic phases arecombined, washed with a brine, dried over magnesium sulfate, filteredand then concentrated. 3,4,5-Trinitropyrazole is obtained in the form ofan orange gum with a crude yield of 80%. The NMR and IR analyses are inaccordance with those obtained with the product of Example 3.

Example 4

600 mg of 4-amino-3,5-dinitropyrazole are added all at once to awell-stirred mixture of sodium persulfate (3 g), 60% hydrogen peroxide(2.5 g), and concentrated sulfuric acid (4 g) at ambient temperature.The reaction mixture is stirred for 8 hours and then extracted 5 timeswith dichloromethane (5*20 mL). The chlorinated phases are combined andare dried over magnesium sulfate, filtered, and then concentrated undervacuum. This gives 325 mg of pure product (47% yield).

The structural formula of said product and the results ofphysicochemical analyses (¹H, ¹³C, and ¹⁴N NMR and MS), which confirmthe structure, are given in Table 1 below.

Example 5

202 mg of 3,5-dinitropyrazole are dissolved in 6 g of concentratedsulfuric acid. 4 g of fuming nitric acid are added rapidly at ambienttemperature. Subsequently, using a dropping funnel, 6 g of sulfuricoleum containing 60% SO₃ (mass titer) are added. The temperature of thereaction mixture is allowed to rise. The mixture is subsequently heatedat 70° C. for 1 hour. The reaction mixture is left to cool to ambienttemperature before being hydrolyzed in 30 g of ice. The mixture isextracted 3 times with ethyl acetate. The organic phases are combinedand are washed with saturated sodium chloride solution, dried overmagnesium sulfate, filtered, and then concentrated under vacuum. Thisgives 245 mg of pure product (95% yield).

The structural formula of said product and the results ofphysicochemical analyses (¹H, ¹³C, and ¹⁴N NMR and MS), which confirmthe structure, are given in Table 1 below.

Example 6

140 mg of 3,4,5-trinitropyrazole are added all at once to a solution of200 mg of sodium hydroxide (10 mL). The mixture is heated at reflux for3 hours. The mixture is subsequently acidified to a pH of 1-2 using 10%hydrochloric acid solution, then extracted with ethyl acetate 3 times.The organic phases are combined and are dried over sodium sulfate,filtered, then concentrated under vacuum. The solid residue is taken upin 10 mL of dichloromethane and then filtered. 40 mg of yellow solid arecollected in this way.

The structural formula of said product and the results ofphysicochemical analyses (¹H, ¹³C, and ¹⁴N NMR), which confirm thestructure, are given in Table 1 below.

-   -   Said Table 1 is given below.

TABLE 1 Example 1, 2 3, 3′, 4, 5 6 formula

¹H NMR (ppm) 7.31 (broad) 12.3 (broad) 11.4 (very broad) ¹³C NMR (ppm)109.8, 148.7, 150.3 122.6 (t), 143.2 135.2, 139.9 ¹⁴N NMR (ppm) 359348.9 310.5, 355.8 MS CI⁺ (NH₃): 174 EI: 203 / CI⁻ (NH₃): 202 Meltingpoint by 204 188 193 DSC (°C.) (decomposition)

Furthermore, the structure of the products obtained in the examples wasconfirmed:

1 and 2: 5-amino-3,4-dinitropyrazole

3, 4, and 5: 3,4,5-trinitropyrazole

6: 4-hydroxy-3,5-dinitropyrazole by X-ray diffraction.

The results obtained are shown, respectively, in attached FIGS. 1, 2,and 3.

With reference to FIG. 2, it is possible to specify that the smallestcrystal lattice contains two molecules. The occupation factor of theproton is 0.5 on each nitrogen atom present in the pyrazole ring.

With reference to FIG. 3, it is possible to specify that the moleculecrystallizes in the presence of 2/3 of a molecule of water.

Example 7

With argon blanketing at 10° C., 17 mg of sodium hydride are introducedinto an anhydrous acetonitrile solution (10 mL) containing 130 mg of3,4,5-trinitropyrazole. The evolution of hydrogen is immediate andsubstantial. The reaction mixture is stirred while being left to returnto ambient temperature. 400 μL of methyl iodide are then added rapidly,and then the mixture is heated at reflux for 2 hours. The mixturebecomes brown over time as a result of the formation of iodine. It isthen left to cool, before the mixture is flooded in 50 mL of distilledwater. The product is extracted three times with chloroform. The organicphases are combined, dried over magnesium sulfate and evaporated to give105 mg of yellow liquid. The product (N-methyl-3,4,5-trinitropyrazole)is purified on silica gel. 91 mg (66% yield) of very pale yellow solidare collected in this way. ¹H NMR (CDCl₃) (ppm): 4.42 (s). ¹³C NMR(CDCl₃) (ppm): 43.2 (CH₃), 123.5 (t), 137.7 (t), 148.8 (m). ¹⁴N NMR(CDCl₃) (ppm): 343.9, 345.3, 348.0. DSC: melting point: 91.3° C.;evaporation temperature: 243° C.

Example 8

24 mg of sodium hydride (0.98 mmol) are added to a cold solution (0° C.)of 3,4,5-trinitropyrazole in dilution in 10 mL of anhydrousacetonitrile. After a few minutes, Pic-O—NH₂ is added, and then themixture is left to return to ambient temperature. The mixture is stirredfor 3 days. The sodium picrate (yellow solid) which precipitates fromthe mixture is isolated by filtration. The filtrate is subsequentlyevaporated to dryness. The product is then purified on silica gel with aheptane/AcOEt mixture (3/1, v/v). The fractions containing the productare combined and then concentrated under vacuum at 20° C. until theproduct precipitates. 55 mg of white solid(N-amino-3,4,5-trinitropyrazole) are collected in this way. DSC: meltingpoint: 130.5° C.; decomposition temperature: 239° C. ¹H NMR (CD₃NO₂)(ppm): 7.07 ((broad) s). ¹³C NMR (CD₃NO₂) (ppm): 123.1 (t, J_(CN)=17 Hz,C(4)-NO₂), 136.5 (t, J_(CN)=17 Hz, C—NO₂), 140.8 (broad, C—NO₂). INEPT¹⁵N NMR (CD₃NO₂) (ppm): −288.7 (NH₂, J_(NH)=74 Hz). ¹⁴N NMR (CD₃NO₂)(ppm): −31.7, −33.3 (fine), −36.7 (fine). ¹H NMR (CD₃CN) (ppm): 6.92((broad) s). ¹⁴N NMR (CD₃CN) (ppm): −28.3, −29.8 (fine), −33.4 (fine),−68.2. MS (EI): 218.

-   -   Attention was focused on the properties and performance        characteristics of the products (compounds) of the invention        prepared in Examples 1 to 6 above.        a) Sensitivity and Thermal Stability

The sensitivity of the products of the invention and, for comparison,that of ONTA, of HMX and of HNIW (ONTA=5-nitro-1,2,4-triazole-3-one,HMX=octogen, HNIW=CL20=hexanitro-hexaazaisowurtzitane) were assessedwith regard to external attacks of mechanical and electrostatic type bymeans of impact tests, friction tests, and electric spark tests.

The tests carried out are presented below.

Impact sensitivity: The test carried out corresponds to that describedin standard NF T 70-500, which is itself similar to the UNO test 3a)ii)from the “Recommendations on the Transport of Dangerous Goods—Manual ofTests and Criteria”, fourth revised edition, ST/SG/AC.10/11/Rev.4, ISBN92-1-239083-8ISSN [French version] 1014-7179. By a minimum series of 30tests, a determination is made of the energy giving rise to 50%(Bruceton method of result analysis) of positive results of an explosivematerial subjected to the impacts of a drop hammer. The substance undertest is confined in a steel device composed of 2 rollers and a guidering. By modifying the mass and the height of drop of the hammer; theenergy can be varied from 1 to 50 J. In view of the small quantity ofmaterial available for some of the products tested, a reduced number ofreproducibility tests was carried out for said products, relative to therecommendations of the NF T 70-500 standard.

Friction sensitivity: The test carried out corresponds to that describedin the standard NF T 70-503, which is itself similar to the UNO test3b)ii). By a minimum series of 30 tests, a determination is made, usingthe Bruceton method, of the force which gives rise to 50% of positiveresults of an explosive material subjected to friction. The substanceunder test is placed on a porcelain plate of defined roughness, which ismoved in a single back-and-forth movement with an amplitude of 10 mm anda speed of 7 cm/s in the empty state, relative to a porcelain peg whichrests on the substance. The force applied to the porcelain peg which isdrawn over the substance can vary from 7.8 to 353 N. In view of thesmall quantity of material available for some of the products tested, areduced number of reproducibility tests was carried out for saidproducts, relative to the recommendations of the NF T 70-500 standard.

Sensitivity to ignition by electric spark: The test carried out is atest developed by the Applicant, with no NF or UNO equivalent. Thesubstance under test, disposed in a boat with a diameter of 10 mm and aheight of 1.5 mm, is placed between 2 electrodes and is subjected to anelectric spark with a variable energy of 5 to 726 mJ. The system isobserved to determine whether there is a pyrotechnic event or not, and adetermination is made of the energy threshold at which initiation of thesubstance is no longer assured. This value is confirmed by 20 tests insuccession. In view of the small quantity of material available for someof the products tested, a reduced number of reproducibility tests wascarried out for said products.

The thermal stability in turn was determined as follows.

Thermal stability: The thermal stability is analyzed by the method ofdifferential thermal analysis (DSC). Differential thermal analysisconsists, within a given temperature range, in characterizing a productby studying the thermicity of the transformations and reactions which itundergoes when subjected to an increase in temperature. The transitiontemperatures are detected by modifying the heat flow used to heat thesample. The method allows a distinction to be made between the fusiontemperatures (m.p.: melting point), boiling temperatures (b.p.: boilingpoint), and decomposition temperatures (dec.: decomposition).

The results obtained are reported in Table 2 below.

TABLE 2 Sensitivity static Thermal Compound impact friction electricitystability ONTA 22 J >353 N >784 mJ 286° C. (dec.) HMX 4 J 125 N >726 mJ287° C. (dec.) HNIW 2 J 80 N 56-400 mJ 245° C. (dec.) Exs. 1 and 2 >50.1J >353 N >784 mJ 204° C. (m.p.) 214° C. (dec.) Exs. 3, 4, 5 17 J 92N >784 mJ 188° C. (m.p.) 258° C. (b.p.) Ex. 6 4.9 J 183 N >784 mJ 193°C. (dec.) m.p. = melting point b.p. = boiling point dec. = decompositiontemperature

Appreciation of the values indicated in said Table 2 gives rise to thefollowing comments.

The compounds of the invention post relatively low sensitivities in thevarious tests. From a general standpoint, the compounds of the presentinvention are significantly less sensitive than the conventionalexplosive compounds of nitramine type such as HMX (or octogen). Thesensitivities observed for said pyrazoles are similar to that of ONTA oreven, in certain cases, are lower than that of ONTA (an outstandinglyinsensitive explosive). Individually it may be noted that5-amino-3,4-dinitropyrazole is particularly insensitive to the 3 tests(impact, friction, static electricity). This compound therefore provesto be less sensitive than ONTA. The impact sensitivity of3,4,5-trinitropyrazole is close to that of ONTA, which is exceptionalfor a compound possessing such an energy level. This low impactsensitivity is accompanied by a highly appropriate friction sensitivity.4-Hydroxy-3,5-dinitropyrazole, for its part, is clearly less sensitiveto friction and slightly less sensitive than HMX to impact. These safetydata clearly make it possible to consider the use of these compounds inenergetic materials of reduced vulnerability.

The thermal stabilities are high and are appropriate for applications inexplosives and propellants.

b) Performance Characteristics:

The energy level of the products of the invention was determined bymeans of experimental measurement (X-ray analyses) of their density andby means of calculation of their enthalpy of formation.

The performance characteristics were then calculated in explosion andthen in propulsion, for propellant applications, in the presence ofbinders plasticized with nitro oils. The constituent polymers of saidbinders are of energetic type (polyglycidyl azide: PGA) or inertpolyether type (HTPE: hydroxytelechelic polyether).

The performance results in explosion and in propulsion (calculated forsimple compositions without addition of ammonium perchlorate andaluminum) are collated in Table 3 below.

TABLE 3 Detonation Specific rate Specific impulse impulse Enthalpy of(m/s) Simple Simple formation Exp. E/E_(HMX) composition compositionCompounds (kcal/mol) density (V/Vo = 2)* (15% HTPE) (s) (30% PGA) (s)HMX 20.1 1.908 9321 249.9 253.8 100%  RDX 16.7 1.823 9008 250.6 254.392% ONTA −25.7 1.910 8544 / / 72% Exs. 1 and 2 14.4 1.872 8640 220.4230.1 82% Exs. 3, 4, 34.1 1.867 9253 261.3 261.9 and 5 96% Ex. 6 −3.61.92** 8901 234.8 241.9 90% *Detonation energy liberated, kinetic andinternal, for a degree of expansion of the products to twice theirinitial volume. Reference HMX = 100%. **The density of the crystal ofthe hydrated compound (⅔ of water) measured by X-ray is 1.807. The valuegiven in the table is the value calculated for an unhydrated compound.

The results of performance in explosion show that:

3,4,5-trinitropyrazole constitutes a powerful explosive with performanceequal to that of octogen (HMX) for a lower impact sensitivity;

5-amino-3,4-dinitropyrazole, a compound insensitive in all of the tests,with a sensitivity lower than that of ONTA (more particularly toimpact), constitutes an explosive which features 10% extra energyrelative to ONTA.

The results of performance in propulsion show:

in the case of 3,4,5-trinitropyrazole, for applications in simplepropellants, a very important gain in terms of specific impulse values,relative to the values obtained with known nitramines such as RDX andHMX (difference greater than 10 s!). This compound even exceeds theperformance levels of CL20 (the most highly performing energeticmolecule in development known to date). The specific impulse values ofCL20 for simple propellants containing 15% of HTPE binder or 30% of PGAbinder are 260.1 or 261.5 s respectively. Those of3,4,5-trinitropyrazole are 261.3 or 261.9 s respectively.

1. A compound of formula (Ia):

in which: R═NO₂, NF₂, NHOH, OH or NHNH₂; or a salt of said compound. 2.A compound of formula (Ic):

in which R′═NH₂ or a linear or branched C₁-C₄ alkyl group, optionallysubstituted by at least one hydroxy and/or fluoro group.
 3. A compoundas claimed in claim 1, selected from: 3,4,5-trinitropyrazole,4-hydroxy-3,5-dinitropyrazole, 4-hydroxylamino-3,5-dinitropyrazole.
 4. Asalt of a compound of formula (Ia) as claimed in claim 1, whose cationis selected from alkali metal, alkaline earth metal, ammonium,substituted ammonium, hydrazinium, guanidinium, aminoguanidinium,diaminoguanidinium, and iminium cations.
 5. A process for preparing acompound of formula (Ia) or of a salt of a compound of formula (Ia) asclaimed in claim 1, characterized in that it comprises: A) for preparing4-difluoroamino-3,5-dinitropyrazole: fluorinating4-amino-3,5-dinitropyrazole; B) for preparing other compounds of formula(Ia): oxidizing 4-amino-3,5-dinitropyrazole or nitrating3,5-dinitropyrazole to obtain 3,4,5-trinitropyrazole; carrying out asubstitution on said 3,4,5-trinitropyrazole, to give3,5-dinitropyrazoles substituted in position 4 by the radical R═NH—NH₂,OH or NHOH; and C) for obtaining a salt, reacting the compound offormula (Ia) obtained above with a base.
 6. The process as claimed inclaim 5, characterized in that the nitration of 3,5-dinitropyrazole iscarried out in a sulfonitric or phosphonitric medium, containing from 0to 100% by mass of sulfuric, phosphoric or nitric anhydride, at atemperature between 50° C. and the boiling temperature of said medium.7. An energetic composition characterized in that it comprises at leastone compound of formula (Ia) and/or at least one salt of such acompound, as claimed in of claim
 1. 8. The energetic composition asclaimed in claim 7, characterized in that it contains at least 20% bymass of said at least one compound of formula (Ia) and/or of said atleast one salt of such a compound.
 9. The energetic composition asclaimed in claim 7, characterized in that it contains from 90% to 100%by mass of said at least one compound of formula (Ia) and/or of said atleast one salt of such a compound.
 10. An energetic compositioncharacterized in that it comprises at least one compound of formula (Ic)as claimed in of claim
 2. 11. The energetic composition as claimed inclaim 10, characterized in that it consists in a melt-cast explosivecomprising at least one compound of formula (Ic).
 12. The energeticcomposition as claimed in claim 11, characterized in that it comprisesat least one other energetic molecule, advantageously at a level ofbetween 10% and 80% by mass.
 13. A compound as claimed in claim 2selected from N-methyl-3,4,5-trinitropyrazole, andN-amino-3,4,5-trinitropyrazole.
 14. A process for preparing a compoundof formula (Ic) as claimed in claim 2, characterized in that itcomprises: obtaining 3,4,5-trinitropyrazole by oxidation of4-amino-3,5-dinitropyrazole, nitration of 3,5-dinitropyrazole, oxidationof 5-amino-3,4-dinitropyrazole or diazotization of said5-amino-3,4-dinitropyrazole; obtaining its anion; carrying out anucleophilic substitution on said anion.
 15. The process as claimed inclaim 14, characterized in that the nitration of 3,5-dinitropyrazole iscarried out in a sulfonitric or phosphonitric medium, containing from 0to 100% by mass of sulfuric, phosphoric or nitric anhydride, at atemperature between 50° C. and the boiling temperature of said medium.16. The energetic composition as claimed in claim 7, characterized inthat it contains not more than 80% by mass of said at least one compoundof formula (Ia) and/or of said at least one salt of such a compound, ina binder.
 17. The energetic composition as claimed in claim 10,characterized in that it contains at least 20% by mass of said at leastone compound of formula (Ic).
 18. The energetic composition as claimedin claim 10, characterized in that it contains from 90% to 100% by massof said at least one compound of formula (Ic).
 19. The energeticcomposition as claimed in claim 10, characterized in that it containsnot more than 80% by mass of said at least one compound of formula (Ic).20. A compound of formula (Ia):

in which: R═NO₂, NHOH, OH or NHNH₂; or a salt of said compound.
 21. Acompound of formula (Ia):

in which: R═NO₂, or a salt of said compound.